Shock absorbers for railway cars



M k I H. W. MULCAHY ET AL SHOCK ABSORBERS FOR RAILWAY CARS Filed May 18, 1959 May 2, 1961 Inventors WMuIcahy By W 9 Atty.

Harry Donald R.H olm SHOCK ABSORBERS FOR RAILWAY CARS Harry W. Mnlcahy, Chicago Heights, and Donald R. Holm, Markham, BL, assignors to W. H. Miner, Inc., Chicago, 111., a corporation of Delaware Filed May'18, 1959, Ser. No. 813,921 4 Claims. (Cl. 213-221) This invention relates to shock absorbers for railway cars andparticularly to mechanisms of the buffer type comprising a casing containing friction and resilient elements and embraced by a telescopically movable sleeve or buffer head.

The present invention provides a buffer having an initial soft resistance to closure followed by increasingly hard resistance to further closure and wherein ease of assembly or disassembly is attained while preventing rotation of the buffer head relative to the casing during use and wherein the means by which such object is atinwardly projecting transverse lugs integral with the casing at such open end; of a tubular open-ended buffer head movably telescoped over the open end of said casing and having a front wall closing the other end of said head; means limiting outward movement of'the head away from said casing: friction shoes within said casing and slidable interiorly therealong; a wedge block engageable with said shoes, an opening in said wedge block, a plurality of lugs extending outwardly from said wedge block and engageable with said casing lugs; a locking bar disposed in nonrotational engagement with said wedge block, means on said bar in non-rotational engagement with means on the front wall of said head; and resilient elements located in the casing to respectively resist inward movement of the shoes and of the locking bar.

Other objects of this invention will, in part, be obvious and in part appear hereinafter.

This invention is disclosed in the embodiments thereof shown in the accompanying drawing and it comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth and the scope of the application as indicated in the appended claims.

Referring now to the drawing, Figure 1 is a view in elevation of the shock absorbing mechanism according to the invention, portions being broken away along the sectionline 11 of Figure 2, for clarity, and

Figure 2 is a transverse end view substantially along the section line 22 of Figure 1.

In general, the shock absorbing mechanism or buffer of this invention comprises an end cap A telescopically movable about the open end of the tubular casing or cylinder B, having a wedge block C biased outwardly thereof by resilient means D which reacts against friction shoes E in contact with the wedge block C, and a locking means F interconnecting the end cap A and the wedge block C r to prevent relative rotation of these two members when the mechanism is in assembled and operable condition.

From Figures 1 and 2 of the drawing, it will be seen that the cylinder B is of substantially tubular cross section, having an integral rear wall closing one end thereof and having its other end open for the reception of means presently to be described. Flanges lzextend Patented May 2, 1961 laterally from said rear wall 10 to provide extensions 'for securing the cylinder in an appropriate position on p the end of a ra1lway car in a conventional manner, such as 'V-shaped interior friction surfaces 24 (see Figure 2),

tapering inwardly from the open end of the cylinder toward the central longitudinal axis of the cylinder as best seen in Figure 1. Exteriorly of the cylinder are three equally circumferentially spaced lugs 26 extending out- 1 wardly of the wall 16 for mating engagement with flanges 28 provided on the end cap A. The flanges 28 are formed at the rear end of enlarged portions 30 which are a continuation of the wall 32 merging with the head 34 of the end cap A. The enlarged portions 30 are of substantially twice the circumferential distance as compared with the corresponding dimension of the lugs 26 and are provided with a recess 36 which will accommodate passage of the lugs 26 whereby the end cap may be, rotated about 7 its longitudinal axis to place the lugs 26 in abutment with the flanges 28 and'thus limit outward movement of the head away from the casing.

The wall 32 of the end cap A is tubular and as shown in the drawing is telescopically slidable or movable 'over the end of the cylinder adjacent to the open end thereof.

' The head 34 is circular and has a convex outer face constituting the buffing surface proper usual in shock absorbing mechanisms of this type.

Extending from the inner surface of the head 34 is a projection 38 preferably of hexagonal configuration. The projection or boss is integral with the head 34 of the end cap.

The wedge block C is in the form of a hollow block having three laterally and outwardly extending lugs 40, each engageable with inwardly extending lateral lugs 42 provided on the interior wall of the cylinder to limit the outward movement of the wedge block C relative to the cylinder B. Between each of the equally spaced lugs 40 on the wedge block, wedging surfaces 44 are provided,

such surfaces being engageable with corresponding wedgingsurfaces 46 on the friction shoes E which are in contact with the casing friction surfaces 24 and which are biased outwardly of the cylinder B by the spring 22.

Extending longitudinally through the Wedge block C is an opening preferably in the form of a hexagonal bore 47 which serves to slidingly receive a hexagonal locking key 48 having a hexagonal recess 50 in mating engagement with a hexagonal boss 38. The locking key or bar 48 has an opening 52 and a chamber 54 for the reception of a T-shaped bar which is inserted through opening 56 in the rear wall It) for assembly of the mechanism. The rear end of the locking bar 48 is in biased engagement with the inner spring 20 which extends through the wedge block bore 47. The configuration of the boss 38 is complementary to the configuration of the recess 50 and preferably is hexagonal but could be of any other shape which would prevent relative rotation between such members. Likewise, the longitudinal opening or bore 47 in the wedge block is of a complementary configuration to the exterior of the locking bar 48 and as shown is hexagonal but could be of any other configuration which would prevent relative rotation between these two elements.

The resilient means D, shown as comprising a pair of nested coil springs 20 and 22, is under an initialcompression and is disposed within the cylinder B so that the outer spring 22 has its forward end bearing against the shoes E and its other end bearing directly against the rear wall 10. The inner spring 29 is disposed to have its forward end bearing against the locking bar 48, thus allowing initial movement of the cap A to take place before such cap contacts and actuates movement of the wedge bring into operation the combined resistance of springs 20 and 21 together with the friction clutch comprising the wedge block C, the shoes E, and the friction bore 24 to provide a high resistance to further movement of the end cap A relative to the casing B.

To assemble the shock absorbing mechanism of this invention, the cylinder B is placed with its open end uppermost, the coil springs 20 and 22 are nested within the cylinder B, followed by placement of the shoes E and the locking bar 48 upon such springs in the upper portion of the cylinder. The wedge block C is then placed in position by passing the central bore 47 of the wedge block over the locking bar 48 until the wedge block rests with its lugs 40 in contact with the upper portions of the shoes E. An assembly tool, (not shown), consisting of a ring of greater inside diameter than the outside diameter of the wedge C and having depending fingers designed to contact the top surfaces of the shoes E and straddle the lugs 40 of the wedge block is then used to depress the shoes against the resistance of spring 22. After the shoes B have been displaced a sufficient distance rearwardly toward wall 10, the wedge block C is depressed downwardly or rearwardly and rotated approximately 30 degrees so that the wedge lugs 40 register beneath the casing lugs 42. Pressure on the assembly tool is then released and the shoes E, under the bias of spring 22, return to their assembled position as shown in Figure 1. Of course, the wedge block C may be assembled with the casing B and the outer spring 22 before the inner spring 20 and the locking bar 48 are placed in position.

If the inner spring 20 and the locking bar 48 have not previously been positioned within the casing, such spring can now be inserted through the bore 47 of the wedge block and nested within the casing inside the outer spring 22 and the locking bar 48 can be then disposed on top of the front end of the inner spring 20. A tool (not shown) having a T-head at one end is then inserted through the hole 56 in the rear wall of the cylinder, passed through the interior of the spring 20 and inserted through the opening 52 and into the chamber 54 of the locking bar 48. The chamber 54 and opening 52, in elfect, form a T-slot for the reception of the T-headed tool. Once said tool is in position, it is rotated 90 degrees to eifect engagement with the interior shoulders of p the chamber 54 and is then drawn rearwardly and held in such position to compress the inner spring 20 and depress the locking bar 48 within the bore in the wedge block, such movement of the bar 48 being approximately half its length. The cap A is then placed over the front end of the cylinder B so that the recesses 36 pass over the lugs 26 on the cylinder. The cap A is then rotated slightly until the lugs 26 are in abutting engagement with the flanges 28 on the walls 32 of the end cap A. At this point during assembly, the depressing force applied to the T-shaped tool is released, permitting the spring 20 to bias the locking key 4-8 upwardly until the recess 50 in the key 48 is fitted about the boss 38 projecting from the inner wall of the head 34, and the tool is removed.

From the foregoing it will be appreciated that this invention affords a shock absorbing mechanism having an "initial soft spring action during theinitial travelof -the cap inwardly or rearwardly toward the cylinder and that thereafter high frictional resistance is encountered due to the wedge block, shoes, and friction surface in the casing coming into operation as a friction clutch mechanism. The locking key arrangement mating with the hexogonal protuberance from thehead and with the hexagonal bore in the wedge affords a simple structure for assembling the shock absorbing mechanism and maintaining same in operating condition or for disassembly of the components if required.

Since certain changes can be made in the foregoing construction and different embodiments of the invention can be made without departing from the spirit and scope thereof, it is intended that all matters shown in the accompanying drawing and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. In a shock absorbing mechanism for railway cars, the combination with a tubular casing having an open end and inwardly projecting transverse lugs integral with the casing at such open end; of friction shoes within said casing and slidable interiorly therealong; a wedge block in engagement with said shoes; a non-circular opening extending longitudinally through said wedge block, a plurality of lugs extending outwardly from said wedge block and engageable with said casing lugs; a tubular openended end cap movably telescoped over the open end of said casing and having a head closing the other end of said cap, said head being longitudinally spaced from and engageable with said wedge; means limiting outward movement of the end cap away from said casing; a non-circular locking bar disposed at least partially in said wedge block opening, means on said bar in non-rotational engagement with means on said head; and a pair of nested inner'and outer resilient elements located in the casing, the outer element biasing the friction shoes outwardly away from the casing and the inner element biasing the locking bar against the head of the end cap.

2. -In a shock absorbing mechanism for railway cars, the combination with a tubular casing having an open end and inwardly projecting transverse lugs integral with the casing at such open end; of fi'lCUOIl shoes within said casing and slidable interiorly therealong; a wedge block in engagement with said shoes; :1 non-circular opening extending longitudinally through said wedge block, a plurality of lugs extending outwardly from said Wedge block and engageable with said casing lugs; a tubular open-ended end cap movably telescoped over the open end of said casing and having a head closing the other end of said cap, a boss on said head projecting toward the open end of said cap, said head being longitudinally spaced from and engageable with said wedge; means limiting outward movement of the end cap away from said casing; a non-circular locking bar disposed at least partially in said wedge block opening, a recess in said locking bar seated against said boss: the recess in said locking bar, the boss and the opening in the wedge block being of a configuration preventing rotation of the locking bar relative to said boss and to said wedge block; and a pair of nested inner and outer resilient elements located in the casing, the outer element biasing the friction shoes outwardly away from the casing and the inner element biasing the locking bar against the head of the end cap.

other end of said cap, said cap being longitudinally spaced from and engageable with said wedge; means limiting outward movement of the end cap away from said casing; a non-circular locking bar disposed at least partially in said wedge block opening, means on said bar in non-rotational engagement with means on said head; and a pair of nested inner and outer resilient elements located in the casing, the outer element acting on the inner ends of the friction shoes to resist inward movement thereof, the inner offering less resistance than said outer element and partially extending through the wedge block and engaging the locking bar.

4. In a shock absorbing mechanism for railway cars, the combination with a tubular casing having an open end and inwardly projecting transverse lugs integral with the casing at such open end; of friction shoes within said casing and slidable interiorly therealong; a wedge block in engagement with said shoes; at non-circular opening extending longitudinally through said wedge block, a plurality of lugs extending outwardly from said wedge block and engageable with said casing lugs; a tubular openended end cap movably teleseoped over the open end of said casing and having a head closing the other end of said cap, a boss on said head projecting toward the open end of said cap, said head being longitudinally spaced from and engageable with said wedge; means limiting outward movement of the end cap away from said casing; a non-circular locking bar disposed at least partially in said wedge block opening, a recess in said locking bar seated against said boss; the recess in said locking bar,-

References Cited in the file of this patent UNITED STATES PATENTS Haseltine Feb. 7, 1939 Dath Nov. l1, 1947 

